Abstract:

Abstract:Filter membrane clogging problem of prefabricated vertical drains (PVD) usually presents in dredged clays by vacuum preloading.For four kinds of drainage plate membrane,the physical and mechanical tests were carried out.The environmental scanning electron microscope used to observe membrane pore structure rules.The essential factors of gradient ratio were comparative analyzed by filter clogging test.The filter membrane clogging mechanism was proposed in summary,and the anti-clogging criterion was established.It should be reference for future engineering.

Abstract:Considering some features of vacuum preloading technique of improving shallow ultra-soft soil foundation,we establish the consolidation theory of sand drains foundation of shallow ultra-soft soil.Its analytical solutions are obtained based on the non-uniform distribution of negative pressure boundary condition.The analytical solutions are closer to the practical engineering,and its calculation accuracy can meet the engineering requirements.

Abstract:The large-diameter steel cylinders are applied to harbor and sea-crossing engineering.But there is still a lack of grasp of the deformation characteristics of the-large diameter steel cylinders.Based on the measured data of the East Artificial Island of Hong Kong-Zhuhai-Macau bridge,we carry out the study on it.The result reveals that with the soil consolidating in the cylinder,the deformation characteristics of the steel cylinder is similar to that of the gravity structure.

Abstract:Theexcess pore pressure produced in the process of pile foundation construction is an important factor affecting the slope stability.Combining a Vietnamese slope and using the numerical method,we analyze the the distribution law of pore water pressure in the slope analysis of piling and resulting impacts range.According to the calculation result of pile before and after the bank slope stability,we analyze and compare of the influence of piling construction on the solpe stability.

Abstract:Based on the sediment test,we simulate the sedimentary situation of dredged silt and investigate the influences of different initial density of soil-water mixture and flocculant.The result shows that the initial density of mixtures has a significant impact on the deposition rate.The change of void ratio change quantity and speed,after the deposition of the void ratio and mud density is inversely proportional to the initial density.The mud deposition velocity and solution is proportional to the valence of cation.Macromolecule PAM is an effective flocculant and can make fine particles flocculate faster.

Abstract:Using the dredger fill sample from Nansha area,we carry out a series of tests in laboratory for the grading,phase,microstructure,element content,and specific surface area analysis.We also obtain the basic physical and mechanical indices by geotechnical experiment.Through comprehensive analysis from the views of physics to chemistry and by the macro way to micro way,we obtain the phase structure characteristics of dredger fill from Nansha area.Test results show that dredger fill is mainly of muscovite and quartz;microstructure appears as flocculation plate;the mass fraction of elements O & Si constitute the majority.The specific surface area is less for clay minerals,so it causes relatively weak minute electric field and combined water film.

Abstract:The different acceptance criteria of ground improvement should be proposed for different stratum,especially for granular soil and cohesive soil.Therefore,it is important to use suitable soil classification method to classify the granular soil and cohesive soil.There are 200 CPT tests,SPT boreholes and laboratory tests carrying out in new Doha port project.Then the data will be analyzed and compared among four different soil classifications.It is shown that the different zone from four methods can reveal an apparent grain size distribution.But for the distinction of granular soil and cohesive soil,the Robertson（1990）method can give the best result and the Robertson（1986） takes second place.The Schmertmann and Douglas method give the worst result which will classify the cohesive soil with fine contents between 35% and 55% as granular soil.

Abstract:The surface subsidence is a direct index indicating in unloading time,and the calculation accuracy has become one of the difficulties faced by all kinds of engineers.To study the dynamic change of reinforcement effect with a soft foundation construction process,the measured data of surface subsidence has been converted to the same interval by hermite interpolation in this paper.Base on the conversion results,GM(1,1)model and the corresponding function with time has been established to predict the surface settlement in different time.The results of analysis showed that the calculation accuracy by the GM（1,1）prediction model is the first level,which could well predict the surface subsidence in different time,meanwhile,it would provide reference and guidance for solving the related complex settlement prediction problems in the future.

Abstract:The foundation pit of Shajing pumping station,which is with a deep silt layer and deep excavation,locates in the deep thick soft ground area and.The simulated calculation for the support scheme by adding virtual tension indicates that the internal stress bending moment can’t meet the requirement for the retaining pile of deep foundation pit stipulated in the code.So,we propose an optimized scheme for the foundation pit.By the comparative analysis of the site construction monitoring data and the calculation data,we prove the reasonableness of optimized program.

Abstract:When the bearing capacity of ground is satisfactory,the settlement is one of the other main criteria for the ground improvement.In Doha new port project,two embankment tests are designed respectively for two types of ground improvement areas,by which the settlement of each point after a long time is obtained.The settlement combined with CPT results is to be analyzed by splitting summation method and parameters inversion method to get the constrained modulus of the soil and then predict the ground settlement.The method presented provides a basis for this project and future similar projects.

Abstract:Common means and methods for monitoring and measurement in improvement of soft soils with the vacuum surcharge preloading technique are introduced.The results of improvement of soft soils with the vacuum preloading technique are analyzed by jointly using the means and methods of surface settlement monitoring and measurement，measurement of pore water pressure，monitoring and measurement of layer settlement and observation of ground water in the light of engineering cases，which may serve as reference for the design and implementation of soft soil improvement projects.

Abstract:Due to high temperature,rainfall and large wheel pressure load,damages occur in port roads of south China area.The bearing capacity of pavement base determines the performance of pavement in port.Considering the deep soft properties of soil,the pavement base reinforced with geogrid is simulated with finite element method.The result shows that the results of the pavement base reinforced with geogrid simulated by finite element method correspond with the results of field section;There is an inverse relationship between the deflection and the ultimate load.The smaller the deflection,the larger the ultimate load.It indicates that geogrid is capable of improving the bearing capacity of pavement base,and the effect is better when the grogrid is placed near the surface layer.

Abstract:Aiming at the problem of stability and safety of deep foundation pit after water and soil bursting,we adopt the finite element software ANSYS to analyze the excavation of foundation pit,and calculate the stress and deformation under different working conditions.Based on the comparison of calculation and monitoring data,we evaluate the safety of foundation pit,and put forward solutions.The results indicate that water bursting has little influence on the compresol pile of the foundation pit.However,the deformation of soil and girder change greatly.By the solution measures,the safety performance of foundation pit still is guaranteed.

Abstract:The service life of Hong Kong-Zhuhai-Macao bridge,which crosses the Pearl river estuary,is designed as 120 years.How to improve the durability of concrete structure located at the open sea with high temperature and humidity became one of the most important issues for the bridge construction.The systematical research on the concrete durability was carried out before and during the construction period based on the engineering practice.Based on the research,the strategies and measures for the durability design,construction and maintenance,which were applied to ensure the service life of 120 years,are expounded.

Abstract:For the 120-year design service life,we expound the principle of basic performance design of marine high-performance concrete for main structures of the Hong Kong-Zhuhai-Macao bridge.Based on the influencing factors of concrete long time durability of exposure test,we study systematically the influence of parameters of mix proportion on the properties of concrete.The ideas and methods of preparation of long service life marine high-performance concrete which satisfies the requirements of workability,strength,durability and volume stability for different structures of bridges and tunnels are presented.

Abstract:Generally,concrete structures are under various stress state,but it is difficult to reflect the concrete structures durability in lab tests,which is often researched by the free-state concrete specimens.This paper probes into the influence of constant compressive load and flexural load on resisting chloride penetration in marine concrete by changing the load levels.The results show that both the chloride concentration among the pure bending section in concrete at a given depth and the chloride penetration depth in concretes increase with the increasing flexural load level.But the chloride concentration in concrete at a given depth and the chloride diffusion coefficient of concrete decrease first and then increase with the increasing compressive load.It can improve the anti-penetration of chloride for concrete when increasing compressive load at low level.Furthermore,there is a significant correlation between the flexural load levels and the constant load factor when expressed as an exponential function for typical high-performance concrete mix.The influences of flexural loads on chloride diffusion coefficient shall be considered in durability design of concrete structures.

Abstract:A pre-embedded durability monitoring sensor,which of it could monitor corrosion potential of rebar,corrosion rate of rebar,chlorine ions concentration and pH for concrete structures was prepared.The properties were also investigated in concrete in laboratory.The results show that the monitoring results could reflect the variety trend of the corrosion potential of rebar,the corrosion rate of rebar,the chlorine ions concentration and the pH value of the concrete structures.It could be used to monitor the durability status of the concrete structures.

Abstract:This study investigated the definite forms of several kinds of cracks,analyzed and discussed the cause of each kind of cracks according to the current situation of the cracks on surface layer of the dolphin type berth on high piles.Then put forward the measures for prevention and control of the cracks on wharf surface according to the specific situation of the construction.

Abstract:In order to improve the accuracy of detection and assessment,we need to distinguish the type and cause of the crack in the detailed investigation of classifying assessment,and recognize the structural problems in the structures according to the cracks.Starting from common cracks in harbor hydraulic structures,we analyze the causes of the common cracks,discuss the crack limit standards and classifying standards,and expound the actual application of crack classification and assessment in hydraulic structures based on a real case of detection and assessment.

Abstract:The influence of hydrophobic poreblocking ingredient (HPI) on the workability,mechanical property,and durability of concrete with different strength grades is studied.The research result shows that the HPI can improve the fresh concrete’s workability and reduce water absorption of concrete significantly by more than 50%.The HPI can enhance concrete chloride ion’s penetration resistance at the same time.It can reduce the early concrete strength,but it has no obvious difference at the later stage.The PI was used in Fanhegang bridge and Donghua bridge and improved the durability of concrete structure significantly.

Abstract:Cracks have significant impact on concrete durability.Electro-deposition is a potential rehabilitation method.Nevertheless much effort has to be devoted before it becomes a mature technique.The investigation on the parameters of crack closure by electrodeposition shows that satisfactory rehabilitation effect can be achieved using solution of Mg(NO 3) 2 and current density of 0.5 Am2.The compressive strength of concrete is improved after treatment.

Abstract:With the development of river shipping,the number of locks gradually increased and the lock’s sizes are increased.The concrete crack becomes a prominent problem day by day.Prevention of concrete cracks and reinforcement corrosion is of vital importance to guarantee the service life of lock projects.This paper analyzes the cause of concrete crack of lock engineering,and control measures for concrete cracks are put forward from the control of raw material and mix proportion of concrete,temperature control,construction technology and constitution design.

Abstract:Based on the galvanic anode cathodic protection engineering of steel pipe piles in Angola LNG terminal,this paper introduces the design,construction and acceptance method for the galvanic anode cathodic protection system of steel pipe piles in the brackish water and shallow water environments，which provides an important experience and basis for the implementation and acceptance method of galvanic anode cathodic protection system in special environments,just like brackish water and shallow water.

Abstract:The temperature distribution is closely related to the crack of large volume concrete,and the thermal conductivity of concrete is the most important parameter for the analysis of the temperature distribution.This paper investigates the test method of thermal conductivity,including the cylinder method,guarded hot plate method,and heat flow meter method,and the test results are between 0.37～3.99 W(m?K).According to the temperature monitoring results of Anrenpu lock,we simplify the component as a cylinder for the calculation of thermal conductivity,and the calculated thermal conductivity is 0.23 W(m?K).The calculated thermal conductivity is used for finite element simulation of temperature distribution inside the component,and the calculated results coincide well with the actual monitoring results.

Abstract:Reinforced concrete members are the main components in the structure of ports.Studying the component in service after a period of time has important practical significance to study the distribution features of the concrete strength and time-changing law in service after a period of time.Based on a large number of concrete strength testing data,we study the concrete strength for the type of probability distribution by W-test,which verifies the feasibility of using normal distribution,and gives the referential values of concrete strength by various test methods.Based on the real-measured data on the concrete strength of different number of years,we get the relationship between the concrete strength values of rebound method and service life by regression analysis method.

Abstract:The comprehensive damage detection of in-service high-pile wharfs is difficult because the structural type is complex and water operations are needed.Based on the independent research and development equipment,we adopt the pile integrity test equipment named VSP and concrete internal damage CT equipment to carry out detection and assessment on an oil drilling platform wharf after ship collision.The results show that the upper structure and piles can be detected accurately using VSP and engineering CT,and the degree of damage of upper structure and piles can be evaluated scientifically according to the results.It can be promoted as a new detection method of in-service high-pile wharves.

Abstract:In view that some ships can’t berth due to the deviation of dimensions ,we propose a scheme,i.e.sticking angle bars on the original concrete members toextend the original member 1 meter downwards and strengthen its cantilever end as well.Berthing force review and finite element calculation show that the berthing members can meet the requirement of berthing after the renovation.The construction and engineering review also indicates that three years’ port operation is normal and the main steel structure is complete.This case of renovation and strengthening of berthing members may serve as reference for similar projects.

Abstract:In order to detect the force of sheet-pile wharf stick,we adopt the dynamic testing technology to test the frequency of rod using the connection between the internal force and frequency of rod,and get the rod’s internal force.For a sheet pile wharf which has been running nearly 30 years and combining with the characteristics of the tie rod,we test the rod force.The test results show that the rod stress has a great influence on its frequency.So we can test the frequency of rod and deduce whether the rod is rusted off,and calculate the intact rod internal forces at the same time.

Abstract:The super-long rock-socketed pile with large diameter is widely used,but the bearing characteristics and load transfer mechanism is not totally figured out.Aiming at the shortcomings of the existing field test research and numerical analysis,we carried out a case study and numerical analysis of super-long rock-socketed pile based on the Penang second bridge project in Malaysia.An elaborate numerical model was established to study the bearing characteristics of super-long rock-socketed pile with large diameter.The comparison of field test and numerical analysis indicates that the finite element calculation has good agreement with the results of O-cell test,but the bearing capacity by statnamic test is 30% larger than that of O-cell method because of the influence of soil dynamic friction resistance and pore water pressure.The side friction of pile accounts for 90% of the total load.The friction of pile develops gradually from the top to the bottom and distributes nonlinearly along the pile.The actual total side friction is far less than the designed ultimate side friction.

Abstract:To compensate for the existing norms lack in technology applications of harbor concrete structures strengthened by CFRP and solve the spotty problem of components with different corrosive grades strengthened with CFRP,powered by NaCl solution to simulate the corrosive marine environment,RC beams were accelerated corroded to different grades,and the comparison tests of corrosion beams flexural strengthened with CFRP were carried out.By analyzing capacity loss and reinforcement effects of the beams with different corrosion degrees,the effects of corrosion grades on RC beams flexural strengthened with CFRP were studied in this paper and the corrosion threshold between bonded directly with CFRP and bonded after chiseling off in the strengthening of RC Beams were discussed.The results showed that,within a certain corrosion threshold,the corrosion grades had significant effects on the flexural strengthening of corrosion RC beams bonded with CFRP,and bonded directly with CFRP can effectively reduce the width of the main cracks,decrease the cracking time,and improve the capacity and overall stiffness of corrosion beams.However,such strengthening effects became more and more insignificant with the increase of corrosion grade.As the RC beams corroded to a certain level,the directly bonded with CFRP was no more suitable for the strengthening,and the corrosion crack width 1 mm and corrosion section loss rate 15% as the threshold between directly bonded with CFRP and bonded after Chiseling off for the strengthening were determined.

Abstract:Based on the result of pile pressing test,pile pulling test and axial force test,we probe into the distribution law of shaft friction on compressive and tensile load of steel tube piles in deep old deposited soil and draw the conclusions as follows:The mean shaft friction of steel tube pile under compressive load in deep old deposited soil area can reach 76.79 MPa and is about 27.5%～30.6% higher than ordinary clay.The shaft friction of steel tube pile under tensile load can reach 42.4～52.8 MPa.The mean shaft friction of steel tube pile under tensile load is 0.84 times of its under compressive load and about 5% higher than ordinary clay.Along with the increase of penetration and soil thickness,the shaft friction of steel tube pile under compressive and tensile load changes slowly.The research result provides an instruction to the theoretical research and engineering practice of steel tube piles in old deposited soil.

Abstract:以广西北部湾钦州港30万吨级油码头控制楼施工为依托，介绍一种离岸混凝土框架结构整体预制吊装的施工技术，研究混凝土框架结构整体吊装的受力稳定性以及预制、吊运和安装的主要施工工艺，提出该技术的施工控制要点，为今后离岸混凝土框架结构施工提供新的工艺选择以及技术参考。

Abstract:Clip piles play a significant role in enhancing the stability of piles and increasing resistance to the action of water,wind and wave.Currently,there is no specification providing guidance for the design and construction of clip piles.This paper studies the influence of clip pile way,the strength of steel and fixture layer space on the structural strength and stability using relevant norms,structure mechanics and finite element method based on an engineering project.The results provide a theoretical basis for the future design and construction.

Abstract:Some steel tubular piles located at the rear crane rail of Kribi deep sea port can not be driven into the design bearing layer,and the ultimately bearing capacity of them can't meet the design requirements.So we propose a method of optimizing the pile tip,aiming to improve the ultimately bearing capacity of steel tubular pile driven in stiff clay layer.We also carry out a trial piling of three types of pile tip including open-end,semi-closed and closed on the sit and analyze the set,driving stress and bearing capacity according to the survey of set,driving monitoring,high strain dynamic test and the axial compression static test.Finally,the type of closed pile tip is recommended on the basis of the test results.

Abstract:Based on summarizing sinking construction for steel tube piles in deep old deposited soil of 5 projects,conclusions are as follows.The bearing stratum of steel tube pile in deep old deposited soil should be medium coarse sand of 50-blow count SPT or deep old deposited soil of 40-blow count SPT.The coefficient of restitution for pile capacity is 1.26～1.40 and higher than other caly soil.Diesel hammer of D128 or D138 should be chosen for pile driving equipment.The final set should be 2～5 mmblow for second gear and 6～10 mmblow for third gear.Energy transfer coefficient for steel tube piles in deep old deposited soil is 28.5%～47.6%.The total number of blows less than 2 500 is 83.8% of the statistics steel tube piles with diameter 1 000～1 400 mm and pile driving efficiency is highest when the bearing stratum and final set is as above-mentioned.Furthermore,the control standard of pile-sinking construction soil can give instruction to theoretical research and engineering practice for steel tube pile in deep old deposited.

Abstract:The traditional static load test on the bearing capacity of piles in wharf needs to dismantle the upper structures,which costs large workload and long time.Based on the project of pile tests of an old wharf,we elaborate a fast and accurate method of pile static load test which maintains the integrity of the upper structure.The amount of loads was preliminarily determined through analyzing the load sharing ratio of pile by the finite element method.The sensors which can measure the loads on pile were installed on the pile top,and the bearing capacity of two piles were tested successfully by this method.

Abstract:A method is presented for calculating the gravity center of semi-submerged ship based on the hydrostatic data and tank data.The control points of stability changed over ship draft is obtained from stability curve.Then,the construction feasibility of loading the large caisson and special shaped caisson is determined by comparing the height and extreme height of the gravity center of semi-submerged ship,and a database with query function and calculation function is formed,which can be used to provide references for construction.

Abstract:Mid-span deflection is widely spreaded in prestressed concrete bridges,and the root cause is that the bridge structure in the construction process accumulated unbalanced moment.In order to fundamentally solve the problem,and reduce the unbalanced moment,based on zero bending moment of dead load theory,this paper studies the arrangement of tendon with beeline and curve in concrete bridges and deduces relevant calculation formulas of prestressing tendon layout.The method of prestressing tendon layout is established and verified to be effective by examples,and the mid-span deformation of prestressed concrete bridges is controlled initiatively.